The history:
This project has been slow-cooked for more than a year ago when I first picked up a Datavue with Cyan Omrons. I immediately fall in love with cyan omrons and decide to find another omron keyboard that is compatible with modern computers for daily use. Sadly it is easier said than done. I reached out to others for help and instead of helping, these guys were crazy enough to suggest that we should make a modern board for Omron B3G-S series. After a year of hoarding and R&D, the project is 80% complete, aka presentable for public viewings.

This thread serves as a personal wiki, I will go into details about my personal experiences with Omron B3G-S switches. And hopefully will have some uses for others as well.

Special thanks:
-Noobmaen,cumwagondeluxe, and Mike: Thank you for supporting me all this time, without your 100% blind faith there would never be any board let alone a custom Omron board
- maarten of www.maartenwut.com The pcb designer
- inachie: the second pcb designer that picked up the pace
- senter at foxlab as the manufacturer for the case.

These are the switches I personally own at one point or another.
- Tactile White: always has LED slot for top housing, commonly found in Sony Audio Units

- Linear White: commonly found in NCR board
- Linear Amber(heavy): commonly found in the same NCR board on the spacebar
- Linear Stripe Amber(light): commonly found in the same NCR board on the enter key

The Cons
- 3-pins over-engineering piece of shit switchplate:
Unless you have a professional desoldering gun, I do not suggest harvesting these switches. The pins are the smallest comparing to SKCL/M and MX. Not only that, a little bit overheating will immediately kill the switches. The fail rate for my harvested omrons are about 8%, which is absurdly high comparing to 2% for SKCL/M and 0.5% for MX. In one video Chyros mentioned that these switches are very finicky, I believe partly because the switchplate are made of very soft plastic, it is easy malleable thus permanently destroy the switchplates. I tried both high heat and low heat and the fail rate is still that high around 8-10% per batch. Coupled with the fact that they have 3 pins for no reason, you WILL fuck up.

- The limitation of cap choices
B3G-S omrons are fatter, vertically, compare to SKCL/M. The thicker caps will not work properly with these switches. On the left are SKCL/M native caps and on the right are Omron native caps(all row 3)
1. AEK
2. Next Non-ADB (AE doubleshot)
3. Dell AT101 (AE dyesub)
4. IBM 5140 (IBM dyesub)

5,6,7 are fully depressed with no problem for Row-3 caps
2,3,4 are not fully depressed for Row-3 caps because of the extra nubs inside the caps

The pros:

- Consistency The number one thing that Alps will never get correctly
All housings are the same with branding on top housings
All stems of the same type are consistent in colors (I'm looking at you SKCM Blues)
All stems are perfectly symmetrical, no extra slit/cut like SKCM stems
All switchplates are blacks, despite how shitty these were designed, they are consistent

- Same springs as SKCL/M series: yes you can use aftermarket springs for these switches

- Softer plastic
The housing are made of softer plastic, most likely POM. Hence the bottoming sounds are not as harsh as the SKCL/M series. This in turn makes the linear whites an interesting breed.

- Longer travel distance than SKCM and NO BUMPS
This is a major win for linear B3G-S, absolutely no phantom bumps when you bottom out, couple with the softer plastic housing, this is the perfect stepchild between SKCL and MX if you're looking for shorter travel true linears with muted bottoming sounds.

- Tactile Whites makes sense
At first we were aiming for Linear and Clicky Omrons, but throughout the development phase we realize that Tactile Omrons are the true champion if you want to experience Omrons. The tactile leaves are clipped into the housings, so no matter how much abuses you put on Tactile Omrons, they will never start to click.

Last edited by Delirious on 11 Jun 2019, 04:28, edited 5 times in total.

75% was the decision between Mike and I. At the time there was a void of custom 75%, and all of the 75% did not make sense to us. They all suffer from the boxy look because of the F-row. Then a few months later, I presented the fixed layout to Robotical, he liked it so much that he implemented in his Knight75 board. Ultimately, Omron75 is the fix for 75% whereas Knight75 is a TKL approach to 75%.

Case Design:

The principles: Omron75 represents my thoughts at the time: I am not an innovator, I am a student of the game. I build and use many keyboards and I know what works and what does not work. Hence I applied those ideas into the board. Here are the specs for the Omron75:

I was able to convince E3E and Siaw that Monarch is one of the best case for clicky SKCM's, Mike also thinks that my VE.A is one of the best skcm orange boards out there. We figure it has to do with the plastic inlay that helps with both the sounds and typing feels.

Omron75 and its inspirations

Last edited by Delirious on 11 Jun 2019, 00:45, edited 2 times in total.

Omron B3G-S switches clip onto the plate from below, and there is no way to unclip them unless you desolder the entire board, then turn the plate over, and unclip from underneath. With softer plate material, aka plastic, you can force pull your way, but with tougher plate material you have to desolder the entire board. To combat this problem, the plate for Omron75 are designed with cuts connecting switches of the same row. Instead of having every switch clip into the plate, only switches that fall onto the red line clip into the plate. To unclip the red-line switches, you just have to desolder one extra switch next to the red line

Omron stab hooks are also deadtraps No way to take them out once they clip into the plate

Dogbone stab hook cutout on plate Due to minimum cnc tip from the factory that I use, I have to use dogbone cutout to ensure the correct dimensions for the stab hooks

The case in brass At first we want Stainless Steel, but SS pricing is not reasonable at all due to the difficulty of cnc SS.

Case assembly

Last edited by Delirious on 15 Jun 2019, 00:04, edited 1 time in total.

Excellent write-up. Your hard work paid off in the end result, for sure.

Also this warning hit home for me. I unknowingly ruined a good percentage of my board's micro switch SD sensors desoldering them the other day

Unless you have a professional desoldering gun, I do not suggest harvesting these switches. The pins are the smallest comparing to SKCL/M and MX. Not only that, a little bit overheating will immediately kill the switches.

Impressive. Can you talk a bit about the plate? It's certainly not a run-of-the-mill acrylic or aluminum plate...

Matte finish, 1.2mm Carbon Fiber plate

Why was carbon fiber chosen?

Also, is that gray-on-gray plaid texture an inherent property of carbon fiber surfaces? 'cause I can imagine some people actually wanting cases looking like that... would that be a good or a bad idea?

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Reason for CF: 40% sound and 60% look.

CF was something E3E suggested. The original goal for Omron75 is to replicate the typing experience of the Monarch and VE.A: tough plate resting on a plastic housing/inlay.

-Tough plate for the most consistency all across, some of the best boards are just regular OEM boards with steel plate (Leading Edge, Alps Bigfoot, F_AT,....) and we want to keep that tradition
-Plastic mid piece for warmer sound.

At first I was thinking of going for the typical aluminum or steel plate, however the plan of SS case didnt work out. Brass is "louder" in term of sounding comparing to SS, so I looked to CF to compensate for the sound.

I also tested the board with POM and ABS plate, and SS is going to be next on the list anyway. All of these amount to very little changes anyway because the B3G-S housings are very self-contained.

I'm trying to build some Omron customs myself, but I can't seem to find any loose amber B3G-S. I found those tactiles on Taobao, but the amber listing I found is apparently out of stock. (https://item.taobao.com/item.htm?id=573572735836)
Any ideas?

I'm trying to build some Omron customs myself, but I can't seem to find any loose amber B3G-S. I found those tactiles on Taobao, but the amber listing I found is apparently out of stock. (https://item.taobao.com/item.htm?id=573572735836)
Any ideas?

I got ambers from trading my cyans, board to board. From what I heard, that source for NOS ambers has run dry a while back but the seller never bothers to update the listing. Maybe DrClick could find you another source for NOS ambers.

Amber omrons are heavier than SKCM Blues but not as extreme as SKCM ambers. In my opinion the heaviness comes from the longer travel distance and the lower click position, the clicks happen somewhere in the middle to the end, you experience the click mechanic as you exhaust the switches; very much different from the high to mid click mechanic from the SKCM counterparts.

I also highly recommend buying loose omron switches from Taobao, that would avoid desoldering altogether. I am glad to see B3G-S picks up steam lately, the timing is perfect. Good to see that I was not the only crazy one to appreciate such a hidden gem.

Sweet build! Was wondering about why the cut-out enter key? Was it due to clearance? I'm pretty new here, so do pardon me if the question I asked is common knowledge around these parts.

Edit: Also, what was that IBM badged board you had in the inspirations?

The enter key comes from IBM 5140, which is actually a Big-Ass-Enter key, I chopped it up to fit standard ANSI layout.

The black board with IBM badge in the back is my TragicForce with skcm ambers, using LFkeyboards' pcb. You could say that it was the very first prototype of what I have envisioned for a sandwich board. 90% of all the ideas behind TragicForce tranfers over to Omron75. It was very instrumental and critical. You can see the whole album here.

Ah, to clarify, I'm going to use alps switches I harvested from an AEK.

Oh, in that case you're are good. Those caps are made for SKCL/M specifically. The spacebar is a bit funky, it uses cherry system for stabilizer but the rest of the long keys use alps system. Make sure your plate supports it.

I've had a board in near new condition with some clicky ambers in it for the longest time, but i've been mostly unable to use it since it's so large (A Wang 725 of some sort). I've been looking about for projects that would support these switches, and I have to say this one looks pretty good! Because of the nature of this project's support, I guess I wouldn't be able to use the keycaps (unless you dare attempt to add BAE support, haha).

Very interested if someone is able to find a source for NOS Ambers as well, since with my tooling i'd probably kill every single switch trying to desolder.

I've had a board in near new condition with some clicky ambers in it for the longest time, but i've been mostly unable to use it since it's so large (A Wang 725 of some sort). I've been looking about for projects that would support these switches, and I have to say this one looks pretty good! Because of the nature of this project's support, I guess I wouldn't be able to use the keycaps (unless you dare attempt to add BAE support, haha).

Very interested if someone is able to find a source for NOS Ambers as well, since with my tooling i'd probably kill every single switch trying to desolder.

I'll be keeping an eye on this to see how it fares from here on out.

BAE's are pretty much just ANSI or ISO with additional support in forms of extra stabilizers or pipes. If you want BAE you just need to get a unique one-off plate. I attempted BAE before

I took a look under my cap after what you said. It uses a standard ansi stab with a pipe support right where the |\ key switch would sit. it would be a little wobbly, but I think it might actually work without the barrel at all.

This is fantastic! I absolutely love the way Amber B3G-S feel, but I've never been able to get a working keyboard with them. I still have a dead Wang 725 full of Ambers and a bunch of loose Whites and Ambers that I'd love to finally use.

Since switches seem to be hard to recover has anyone tried using a product called Chipquick which helps lower the melting point of solder?

That's a great suggestion. I've never tried that product but these types of tricks are necessary when working with sensitive switches.

Micro Switch SD has a similar sensitivity (some are super sensitive to heat. Probably even more than these I'd imagine). Polecat's suggestion to me was increasing heat in order to make the solder melt fast and limit the amount of time that you're applying the heat.

I upgraded from a bulb solder sucking iron to a proper desoldering gun. I found that if I set it relatively high (at least in comparison to my old bulb iron), the solder melts and gets sucked up immediately. Since the contact between the pin and the iron is so short, the sensor doesn't even have a chance to get hot. This saved me from ruining many many sensors.

Hey guys, long time no update. I just received the second prototype today and I have 100% happy about the aesthetic and 95% there with construction, this was my fault for mixing up between m3 and m4 spacers without double checking.

Here are the changes:
1. Exaggerated the chamfers to equalize the overall roundness more.
2. Changed to footbar instead of cone feet
3. Changed the angle from 7 degree to 9 degree.
4. Interior: extended the plate's wings by 30mm each to normalize the downstrokes. I noticed the corner keys and middle column were flexing more than needed for the first revision.

Next step:
1. Cerakote and meetup with mike52787 and Zod for second opinion.
2. Send the prototype to Snackthecat at the end of August for third opinion
3. Groupbuy somewhere in September.